Fix update_version script to handle `+` in version numbers.

tool/update_version.sh

diff --git a/tool/update_version.sh b/tool/update_version.sh
index fa776b4..f1ab5f9 100755
--- a/tool/update_version.sh
+++ b/tool/update_version.sh
@@ -29,17 +29,17 @@
 # We could use LAST_VERSION instead of allowing any previous version
 
 # Update the version of all packages.
-perl -pi -e "s/^(\\W*version:) [0-9.dev-]+/\$1 $VERSION/g" $PUBSPECS
+perl -pi -e "s/^(\\W*version:) [0-9.dev\-\+]+/\$1 $VERSION/g" $PUBSPECS
 
 # Update all references to package versions
-perl -pi -e "s/^(\\W*devtools_shared:) \\^?[0-9.dev-]+/\$1 $VERSION/g" $PUBSPECS
-perl -pi -e "s/^(\\W*devtools_server:) \\^?[0-9.dev-]+/\$1 $VERSION/g" $PUBSPECS
-perl -pi -e "s/^(\\W*devtools:) \\^?[0-9.dev-]+/\$1 $VERSION/g" $PUBSPECS
-perl -pi -e "s/^(\\W*devtools_app:) \\^?[0-9.dev-]+/\$1 $VERSION/g" $PUBSPECS
-perl -pi -e "s/^(\\W*devtools_testing:) \\^?[0-9.dev-]+/\$1 $VERSION/g" $PUBSPECS
+perl -pi -e "s/^(\\W*devtools_shared:) \\^?[0-9.dev\-\+]+/\$1 $VERSION/g" $PUBSPECS
+perl -pi -e "s/^(\\W*devtools_server:) \\^?[0-9.dev\-\+]+/\$1 $VERSION/g" $PUBSPECS
+perl -pi -e "s/^(\\W*devtools:) \\^?[0-9.dev\-\+]+/\$1 $VERSION/g" $PUBSPECS
+perl -pi -e "s/^(\\W*devtools_app:) \\^?[0-9.dev\-\+]+/\$1 $VERSION/g" $PUBSPECS
+perl -pi -e "s/^(\\W*devtools_testing:) \\^?[0-9.dev\-\+]+/\$1 $VERSION/g" $PUBSPECS
 
 # Update version defined in the source code in devtools_app.
-perl -pi -e "s/^(\\W*const String version =) '[0-9.dev-]+'/\$1 '$VERSION'/g" ./devtools_app/lib/devtools.dart
+perl -pi -e "s/^(\\W*const String version =) '[0-9.dev\-\+]+'/\$1 '$VERSION'/g" ./devtools_app/lib/devtools.dart
 
 popd